Monitoring devices are frequently used, in particular in motor vehicles, in order to record the state of charge and the state of a rechargeable battery itself, and allow conclusions to be drawn about these states on the basis of the voltage which is dropped across the rechargeable battery and/or the charging current and discharge current of the rechargeable battery.
The monitoring devices, which are also referred to as intelligent battery sensors, normally comprise a measurement element and evaluation electronics. The measurement element is provided, for example, by a measurement resistor (shunt) and connecting zones, by means of which electrical contact can be made with the measurement resistor. The electrical connection between the connecting zone of the measurement element and the evaluation electronics, which are located on a printed circuit board, is normally made by means of a contact element, which is soldered to the connecting zone.
Since the charging current and discharge current of the rechargeable battery flow through the measurement element, it is heated. Particularly high currents occur, for example, during the process of starting the motor vehicle, or in commercial vehicles. The current-dependent heating of the measurement element can lead to destruction of the soldered joint between a connecting zone of the measurement element and the contact element.
One possible way to avoid the disadvantages of a soldered joint between the measurement element and the contact element is disclosed in the subsequently published document DE 10 2004 033 127. This document discloses an apparatus for recording an electrical variable of a rechargeable battery, which has a measurement element connected in series with the rechargeable battery. The connection between the measurement element and evaluation electronics which are arranged at the printed circuit board is made by connecting a connecting element to the measurement element, with a friction fit and/or an interlock.